The present invention refers to a pivot mechanism for motor car doors, e.g. doors of passenger cars.
Nowadays it is traditionally almost only used one type of mechanism for suspending motor car doors, comprising simple, conventional hinges, which have been modified to some extent and which are usually mounted in the side of the forward door opening, and in the forward door edge, respectively, and the opening and closing movements of the door are caused in that the door leaf is allowed to pivot about the common hinge axis.
This is a well-tested solution, which is simple and cheap to manufacture, and which is comparatively reliable. On the other hand it must be established that it is not quite practical for the opening function of the door. As the door is opened, the rear door edge thus will swing out from the side of the car, whereby a space for stepping-in and stepping-out is formed between the rear door edge and the car body. In order to give a reasonable space, guaranteeing fairly free stepping-in and stepping-out, it is required that the door is opened so much that its rear edge is situated about 60 cm outside the side of the car body. Furthermore it is often difficult, not to say impossible, to open the car door so much as required for comfortable stepping-in and stepping-out, due to different obstacles, such as other cars, parked close by in narrow parking lots, or walls and pillars in small villa garages, etcetera.
As an alternative to these conventional door hinges for passenger cars, which thus in the open door position still limit the size of the stepping-in and stepping-out opening, and furthermore require rather big free space along the sides of the car, there are sliding doors of different types, which are used successfully in light transport cars and miniature buses. However this solution is hardly useful for passenger cars, as the mounting of the sliding mechanism and the reciprocating movement of the door leaf are obstructed by the front wheel of the vehicle. For using sliding door leafs it therefore is necessary to let the motion area of the door leaf extend rearwards, and for this reason sliding doors for passenger cars will cause that the car can be made only in a two door version. This is a limitation of the car type, which is not appreciated by everybody. Furthermore it is still difficult to find natural mounting attachments for the sliding mechanisms and it is necessary to design more or less complicated solutions, which mean increase in manufacturing costs and furthermore often make the doors unstable.
Another type of alternative for the common car door hinges are mechanisms, which use pivotable arms, which e.g. often is utilized at buses. In such applications for passenger cars, the position of the front wheels however will limit the usefulness, at the same time as the movement of the door out from the car side remains, and for these reasons, those structures do not constitute any virtual solution of the problem defined.
In U.S. Pat. No. 4 632 447 and U.S. Pat. No. 4 641 881 however, there are described two hinge mechanisms intended for passenger cars and having pivotable arms, which have been adapted for use at passenger cars, but also in these cases the door leaf moves, when opened, a short distance out from the side of the car, at the same time as the size of the door opening is limited.
GB-A-902405 discloses an arm mechanism solution wherein one of the hinges has been provided at a substantial distance from the other for making the system stable, and where the hinge located lowermost is mounted in the middle of the door opening. At opening the lower arm therefore will be a substantial obstacle for stepping-in and stepping-out. The door will also move outwards and this undesired movement can not be eliminated by essentially angling the motion plane for the arms horizontally, as this should mean that the above described problems then should be aggravated to such extent that stepping-in and stepping-out should be rather difficult.